
Re: We get hammered with this all the time in Canada
Ummm... what makes you think there's no duty to be paid for goods crossing from the US to Canada?
Not all types of good require duty, but some do.
http://www.dutycalculator.com/new-import-duty-and-tax-calculation/
On top of that there are additional costs caused by doing business in Canada.
Some goods need certification by Canadian authorities to be legally sold here, etc., etc.
And not just Federally, some of that is Province by Province and selling to just some Provinces creates its own headaches.
And, of course, that entails translating all documentation into French - and being able to support French customers. If a company has to do that, then they need to have a French call centre. US customers won't get burdened by that cost, but it is spread across English & French Canadian customers because they can't charge French speaking customers more.
And there's more...
Most of these costs are fixed rather than marginal costs, so they are spread across a 30mm customer market rather than a 300mm market.